The url structure for the online sales channel is prescribed and unchangeable for routes like that /collections, /pages /products, /search etc.
The most you can do is setup redirects for your created content, but not the predefined routes like /collections or /products.
For those the most you can do is theme customizations to control what content shows, or add meta refresh or javascript redirects.
The /products url is the colllection-list page and template